Span-tastic sight as bridge progresses

Come January, the south span of the new bridge, now being built at the Port of New Hampshire, will be floated into place — an exacting operation that will require a precise fit to within one-quarter of one inch of the piers, said Stephen DelGrosso of Archer Western Contractors.

Work will begin soon thereafter on the north span — concurrently with work on the south span tower, which will rise 200 feet in the air. The north span and tower come next, followed finally by the center span.

For the first six months of 2013, expect a lot of activity, as Archer Western, the contractor for the new Memorial Bridge, works toward a July 6 deadline — which DelGrosso said they'll have no trouble meeting.

DelGrosso gave an update on the Memorial Bridge project Thursday afternoon. He was joined by New Hampshire Department of Transportation officials at the Port of New Hampshire.

The new Memorial Bridge is a first-of-its-kind in the world for several reasons. The truss bridge uses no gusset plates, because, instead of steel girders, the bridge incorporates cold bending of steel in sections.

DelGrosso said, while there were some "glitches" initially in the fabrication of the steel sections, those have been worked out "and the bridge is going together very nicely."

The fabrication work is being done in Claremont by Structal-Bridges. Structal is also spraying on the molten zinc coating which is responsible for the gray color of the bridge — named "Piscataqua Mist" by those voting at the Kittery Block Party last June.

While work has been going on at the Port of New Hampshire, it's also been proceeding at the site of the new bridge. The Scott Avenue approach is essentially completed, and sidewalks are now being installed, DelGrosso said.

Work is nearing the end on the Kittery approach span as well, he said, and "will be substantially done before Christmas."

The project has not been without its challenges, he said. The micropiling work at each pier has not gone as smoothly as expected. So that the piers did not have to be replaced, dozens of 10-inch holes were drilled into them. They were then filled with rebar and cement to strengthen the piers.

From early on, unexpected obstructions such as steel were found in the pier, he said, and workers had to find a way to drill through these obstructions.

"That was probably the biggest problem," he said.

But weather was a factor, as well. For instance, when Hurricane Sandy was barreling up the East Coast, workers had to bring the work barges upriver and secure the site. "Even though it wasn't bad here, we had to take precautions," he said.

DelGrosso said he "can't say enough" about the Port of New Hampshire, which is acting as host for the span work.

"They've been great," he said.

Fact Box

Factoids

• The south and north fixed spans each weigh 600 tons

• Each span section is 300 feet long

• The two towers are 200 feet off the water; the first 20 feet of the tower will be incorporated into the south and north fixed spans and the remaining 120-foot portion will be built following float in

• 18 people are working six days a week, 10-12 hours a day on the south fixed span

• Crews are working around the clock right now completing the micropiling work on the piers